<?php

/**

 * Random_* Compatibility Library

 * for using the new PHP 7 random_* API in PHP 5 projects

 *

 * @version 1.2.1

 * @released 2016-02-29

 *

 * The MIT License (MIT)

 *

 * Copyright (c) 2015 Paragon Initiative Enterprises

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

if (!defined('PHP_VERSION_ID')) {

    // This constant was introduced in PHP 5.2.7

    $RandomCompatversion = explode('.', PHP_VERSION);

    define(

        'PHP_VERSION_ID',

        $RandomCompatversion[0] * 10000

        + $RandomCompatversion[1] * 100

        + $RandomCompatversion[2]

    );

    $RandomCompatversion = null;

}

if (PHP_VERSION_ID < 70000) {

    if (!defined('RANDOM_COMPAT_READ_BUFFER')) {

        define('RANDOM_COMPAT_READ_BUFFER', 8);

    }

    $RandomCompatDIR = dirname(__FILE__);

    require_once $RandomCompatDIR.'/byte_safe_strings.php';

    require_once $RandomCompatDIR.'/cast_to_int.php';

    require_once $RandomCompatDIR.'/error_polyfill.php';

    if (!function_exists('random_bytes')) {

        /**

         * PHP 5.2.0 - 5.6.x way to implement random_bytes()

         *

         * We use conditional statements here to define the function in accordance

         * to the operating environment. It's a micro-optimization.

         *

         * In order of preference:

         *   1. Use libsodium if available.

         *   2. fread() /dev/urandom if available (never on Windows)

         *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)

         *   4. COM('CAPICOM.Utilities.1')->GetRandom()

         *   5. openssl_random_pseudo_bytes() (absolute last resort)

         *

         * See ERRATA.md for our reasoning behind this particular order

         */

        if (extension_loaded('libsodium')) {

            // See random_bytes_libsodium.php

            if (PHP_VERSION_ID >= 50300 && function_exists('\\Sodium\\randombytes_buf')) {

                require_once $RandomCompatDIR.'/random_bytes_libsodium.php';

            } elseif (method_exists('Sodium', 'randombytes_buf')) {

                require_once $RandomCompatDIR.'/random_bytes_libsodium_legacy.php';

            }

        }

        /**

         * Reading directly from /dev/urandom:

         */

        if (DIRECTORY_SEPARATOR === '/') {

            // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast

            // way to exclude Windows.

            $RandomCompatUrandom = true;

            $RandomCompat_basedir = ini_get('open_basedir');

            if (!empty($RandomCompat_basedir)) {

                $RandomCompat_open_basedir = explode(

                    PATH_SEPARATOR,

                    strtolower($RandomCompat_basedir)

                );

                $RandomCompatUrandom = in_array(

                    '/dev',

                    $RandomCompat_open_basedir

                );

                $RandomCompat_open_basedir = null;

            }

            if (

                !function_exists('random_bytes')

                &&

                $RandomCompatUrandom

                &&

                @is_readable('/dev/urandom')

            ) {

                // Error suppression on is_readable() in case of an open_basedir

                // or safe_mode failure. All we care about is whether or not we

                // can read it at this point. If the PHP environment is going to

                // panic over trying to see if the file can be read in the first

                // place, that is not helpful to us here.

                // See random_bytes_dev_urandom.php

                require_once $RandomCompatDIR.'/random_bytes_dev_urandom.php';

            }

            // Unset variables after use

            $RandomCompat_basedir = null;

            $RandomCompatUrandom = null;

        }

        /**

         * mcrypt_create_iv()

         */

        if (

            !function_exists('random_bytes')

            &&

            PHP_VERSION_ID >= 50307

            &&

            extension_loaded('mcrypt')

        ) {

            // Prevent this code from hanging indefinitely on non-Windows;

            // see https://bugs.php.net/bug.php?id=69833

            if (

                DIRECTORY_SEPARATOR !== '/' ||

                (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)

            ) {

                // See random_bytes_mcrypt.php

                require_once $RandomCompatDIR.'/random_bytes_mcrypt.php';

            }

        }

        if (

            !function_exists('random_bytes')

            &&

            extension_loaded('com_dotnet')

            &&

            class_exists('COM')

        ) {

            $RandomCompat_disabled_classes = preg_split(

                '#\s*,\s*#',

                strtolower(ini_get('disable_classes'))

            );

            if (!in_array('com', $RandomCompat_disabled_classes)) {

                try {

                    $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');

                    if (method_exists($RandomCompatCOMtest, 'GetRandom')) {

                        // See random_bytes_com_dotnet.php

                        require_once $RandomCompatDIR.'/random_bytes_com_dotnet.php';

                    }

                } catch (com_exception $e) {

                    // Don't try to use it.

                }

            }

            $RandomCompat_disabled_classes = null;

            $RandomCompatCOMtest = null;

        }

        /**

         * openssl_random_pseudo_bytes()

         */

        if (

            (

                // Unix-like with PHP >= 5.3.0 or

                (

                    DIRECTORY_SEPARATOR === '/'

                    &&

                    PHP_VERSION_ID >= 50300

                )

                ||

                // Windows with PHP >= 5.4.1

                PHP_VERSION_ID >= 50401

            )

            &&

            !function_exists('random_bytes')

            &&

            extension_loaded('openssl')

        ) {

            // See random_bytes_openssl.php

            require_once $RandomCompatDIR.'/random_bytes_openssl.php';

        }

        /**

         * throw new Exception

         */

        if (!function_exists('random_bytes')) {

            /**

             * We don't have any more options, so let's throw an exception right now

             * and hope the developer won't let it fail silently.

             */

            function random_bytes($length)

            {

                throw new Exception(

                    'There is no suitable CSPRNG installed on your system'

                );

            }

        }

    }

    if (!function_exists('random_int')) {

        require_once $RandomCompatDIR.'/random_int.php';

    }

    $RandomCompatDIR = null;

}